High Pressure Effects on the Dynamics and Kinetics of Two Model Biochemical Systems

Pressure effects on rate constants for hydrogen exchange between N-methylacetamide (NMA) and water were measured at pressures up to 5 kbar at three different pH values and temperatures using proton/nitrogen-14 decoupled NMR inversion transfer, and the apparent activation volumes of exchange determined. Hydrogen exchange between NMA and water serves as a model for amide-water hydrogen exchange in peptides and proteins which is sensitive to the local environment of the protons and is used to probe fluctuations in the local conformations of proteins. Hydrogen exchange rate constants were also measured as a function of concentration and pH at ambient pressure at each temperature, and the rate constants of the acid-, base-, and uncatalyzed hydrogen exchange reactions determined. With these values, activation volumes of the acid-, base-, and uncatalyzed exchange reactions were calculated. This is the first time the uncatalyzed activation volume, which is required in hydrogen exchange studies of peptides and proteins at high pressures, had been determined. The temperature dependence of the activation volumes and the catalyzed rate constants was also examined.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Mabry, Stephanie Ann

Contributors dc:contributor

• Jonas, Jiri

• Chemistry, Physical

Language dc:language

eng

Identifier

(MiAaPQ)AAI9717304

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/84361